Known conventional rolling devices have an inner member, an outer member, and a plurality of rolling members, such as balls or rollers, that are disposed between the inner member and the outer member and endlessly circulate between a loaded section formed between the inner member and the outer member and an unloaded section formed on the outer member to allow relative rotational or linear movement of the outer member with respect to the inner member. The rolling devices of this type inherently have a gap between the inner member and the outer member because of its structure, and therefore, foreign matter can enter the gap from the outside in the course of relative slide between the inner member and the outer member. Besides, a lubricant is sometimes introduced into the inner member. In that case, the lubricant has to be prevented from leaking in the course of relative slide between the inner member and the outer member. Thus, the conventional rolling devices have a sealing member to prevent leakage of the lubricant from inside the inner member or entry of foreign matter from the outside.
As an example of the conventional rolling devices having a sealing member, a ball spline will be described. FIG. 9 is a partially cut away perspective view for illustrating the whole of the configuration of a ball spline. FIG. 10 includes diagrams showing a conventional sealing member applied to the ball spline shown in FIG. 9. In particular, FIG. 10(a) is a front view of the conventional sealing member, and FIG. 10(b) is a cross-sectional view of the sealing member taken along the line B-B in FIG. 10(a).
A ball spline 70 shown in FIG. 9 has a spline shaft 71 serving as the inner member and a cylindrical outer sleeve 73 serving as the outer member movably attached to the spline shaft 71 with a plurality of balls 72 serving as rolling members interposed therebetween.
Grooves 71a for rolling members extending in the axial direction of the spline shaft 71 to serve as a track for the balls 72 are formed in the surface of the spline shaft 71. The outer sleeve 73 to be attached to the spline shaft 71 has grooves for loaded rolling members corresponding to the grooves 71a for rolling members. In the grooves for loaded rolling members, a plurality of linear protrusions extending in the direction of the grooves 71a for rolling members are formed.
Loaded paths are formed between the grooves for loaded rolling members formed in the outer sleeve 73 and the grooves 71a for rolling members formed in the spline shaft 71. Unloaded return paths through which unloaded balls 72 moves are formed adjacent to the loaded paths. The outer sleeve 74 has a holder 74 to arrange and maintain the plurality of balls 72 in a circuit configuration.
The plurality of balls 72 are disposed in the loaded paths between the grooves for loaded rolling members formed in the outer sleeve 73 and the grooves 71a for rolling members formed in the spline shaft 71 and in the unloaded return paths in such a manner that the balls 72 can endlessly circulate between the loaded paths and the unloaded paths. Thus, the outer sleeve 73 can relatively move back and forth with respect to the spline shaft 71.
Furthermore, to seal the gap between the spline shaft 71 and the outer sleeve 73, the spline 70 has a conventional sealing member 75. The conventional sealing member 75 is fixed by fitting the sealing member 75 and a retaining ring 76 into an annular groove formed in the inner periphery of the outer sleeve 73 and prevents leakage of the lubricant from inside the outer sleeve 73 or entry of foreign matter from the outside.
The sealing member 75 of this type is disclosed in the Patent Document 1 described, for example. Any conventional sealing member of this type is fitted into the groove formed in the outer member with a retaining ring.
Patent Document 1: Japanese Patent Laid-Open No. 4-300423